cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A353564 Product_{d|n, dA276086(phi(d)), where A276086 is primorial base exp-function, and phi is Euler totient function.

Original entry on oeis.org

1, 2, 2, 4, 2, 12, 2, 12, 6, 36, 2, 108, 2, 20, 54, 108, 2, 180, 2, 972, 30, 180, 2, 8748, 18, 100, 30, 300, 2, 43740, 2, 1620, 270, 900, 90, 24300, 2, 500, 150, 131220, 2, 22500, 2, 24300, 4050, 4500, 2, 1968300, 10, 121500, 1350, 7500, 2, 112500, 810, 67500, 750, 22500, 2, 265720500, 2, 28, 3750, 364500, 450
Offset: 1

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Author

Antti Karttunen, Apr 27 2022

Keywords

Crossrefs

Cf. A000010, A051953, A276085, A276086, A353563, A353565 (rgs-transform).
Cf. also A318834.

Programs

  • PARI
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    A353564(n) = { my(m=1); fordiv(n,d,if(d < n,m *= A276086(eulerphi(d)))); m; };

Formula

a(1) = 1 (as an empty product).
a(n) = Product_{d|n, dA353563(d).
For all n >= 1, A276085(a(n)) = A051953(n).

A353565 Lexicographically earliest infinite sequence such that a(i) = a(j) => A353564(i) = A353564(j), where A353564(n) = Product_{d|n, dA276086(phi(d)).

Original entry on oeis.org

1, 2, 2, 3, 2, 4, 2, 4, 5, 6, 2, 7, 2, 8, 9, 7, 2, 10, 2, 11, 12, 10, 2, 13, 14, 15, 12, 16, 2, 17, 2, 18, 19, 20, 21, 22, 2, 23, 24, 25, 2, 26, 2, 22, 27, 28, 2, 29, 30, 31, 32, 33, 2, 34, 35, 36, 37, 26, 2, 38, 2, 39, 40, 41, 42, 43, 2, 44, 45, 46, 2, 47, 2, 48, 49, 50, 42, 51, 2, 52, 40, 53, 2, 54, 27, 55, 56, 47, 2, 57
Offset: 1

Views

Author

Antti Karttunen, Apr 27 2022

Keywords

Comments

Restricted growth sequence transform of A353564.
For all i, j: A305800(i) = A305800(j) => a(i) = a(j) => A051953(i) = A051953(j).

Crossrefs

Programs

  • PARI
    up_to = 65537;
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    A353564(n) = { my(m=1); fordiv(n,d,if(d < n,m *= A276086(eulerphi(d)))); m; };
    v353565 = rgs_transform(vector(up_to,n,A353564(n)));
    A353565(n) = v353565[n];
Showing 1-2 of 2 results.